1. Field of the Invention
The present invention relates to a method and device for mechanically forming a hollow vessel body and more particularly relates to an effective method and device for mechanically and automatically forming a hollow vessel even when a viscosity of a raw material thereof is considerably low, and a hollow vessel body thus formed.
2. Prior Art
Waste recycling has been considered as an important issue in order to save resources, preserve living surroundings and prevent environmental pollution. One of the most familiar and urgent issues is a reuse of waste paper such as news paper, magazine, etc.
Waste paper is typically reused as regenerated paper, while a paper regeneration process has various industrial problems caused by waste paper treatment to prepare the starting material, residues thereof, relatively high production cost, etc. It is therefore desirable to recycle waste paper as simply as possible without troublesome treatment and addition of additives.
A cost-saving recycle process of waste paper is, for example, to simply slurry paper in water, which is used to form a vessel body such as flowerpots or a block body such as brick. The thus water-slurried waste paper, however, is not useful at all as a starting material to form the above mentioned vessel body because of a poor viscosity although it might sometimes be used for production of paper brick and the like. One of important factors for producing the waste paper vessel body such as flowerpots that the vessel can be formed on a large scale at a low cost while quality thereof is not necessarily high-grade. It seems possible to use a conventional device comprising a jigger, a negative mold and a forming attachment provided with a trowel (hereinafter simply referred to as a jigger unit) for mass-production of waste paper flowerpots, etc. Such a waste paper material, however, can not be shaped into a vessel body by conventional jigger units because of an excessively low viscosity thereof.
When the waste paper material is applied to the surface of a negative mold by means of a trowel, the material is easily repelled from or hardly stuck on the mold so that no shape is formed thereon.
When a vessel body is formed by means of a conventional jigger unit an applicable material is a pottery clay which is freely and easily transformed and water content thereof has been adjusted to appropriate hardness (or softness) enough to keep a vessel shape to be formed. Thus, such a pottery clay can be formed by the conventional jiggler unit without trouble. Conversely, it might be said that the above mentioned jigger unit has been developed only for forming the pottery clay.
However, it is impossible to obtain quality similar to the pottery clay even if a water content of the waste paper material is carefully controlled when the material is prepared by simply slurrying waste paper in water. The slurried waste paper is hardly used as a starting material at a higher water content while it becomes rather dry and decreases a viscosity impracticably at a lower water content.
A slurry of waste paper is sometimes mixed with a solidifying agent or a glue to improve properties of the material, however, such a mixture is different from the environmentally desirable reuse of waste paper as it is and what is worse, the thus mixed material still shows a relatively low viscosity and keeps a rather dryish state.
Although waste paper may be chemically treated to yield a starting material which has similar properties as a pottery clay, the present invention intends to reuse waste paper as it is without adding any chemical agent.
A material of waste paper is conventionally formed by means of press molding. It is necessary to finely distribute the material on the mold surface due to poor flowability thereof, while water extracted therefrom should be released by means of, for example, a partially meshed mold. The product thus formed under such a complicated condition looks quite poor and, in addition, should be reinforced by wax finishing, etc.
According to the present invention, a method and a device for mechanically and automatically forming a vessel body even when a material has low viscosity such as waste paper of lower water content prepared by simply slurrying it in water, the thus formed product looking reasonably good and having sufficient strength, are provided.
It is an object of the present invention to provide a method for forming a vessel body in which a material is charged in a negative mold, pressed to and spread on a mold surface by means of a rotating cylindrical rotary trowel to form a vessel body.
Another object of the present invention is to provide a device for forming a vessel body which comprises an open top negative mold, a ring-like lid member of a negative mold, which inside diameter is smaller than an open top diameter of the mold, a cylindrical rotary trowel which is mechanically fixed to move against an inner surface of the mold within a predetermined range and is at least longer than height of an inner wall surface of the vessel body to be formed, and a trowel drive.
Yet another object of the present invention is to provide a vessel body formed by a method stated above in which there is used a material of extremely low viscosity such as that prepared by slurring waste paper in water.